Signaling system



June 12, 1928. 1,673,124

A. RAYNSFORD SIGNALING SYSTEM Filed May 31, 1927 //v l/EN TOE ARTHURPAVMSFOHD f6 aw A rm RNEY Patented June 12, 1928.

UNITED STATES 1,673,124 PATENT. OFFlCE ARTHUR RAYNSFORD, OF NEW YORK,'N. Y., ASSIGNOR '10 BELL TELEPHONE LABO- RATORIES, INCORPORATED, OF NEWYORK, N. Y., A GORPORATIONOF NEW YORK.

SIGNALING SYSTEM.

a Application filed May 31,

This invention relates to signaling systems and more particularly totelephone exchange systems and means therein under the control of acalling subscriber to control the release of an established connection.

In telephone systems employing machine switching. apparatus .of thepower driven type, the calling subscribers substation set is suppliedwith current for talking purposes from a battery in a trunk circuitassociated with the first selector or so-called district selector, thecurrent passing during the conversation, to the subscribers line throughthe winding of a supervisory relay. This supervisory relay is thus underthe control of the calling subscribefis switchliook and is employed toinitiate the release of the established connection when the callingsubscriber desires to terminate the conversation. In systems of thischaracter, heretofore known, provision has been made to .delay therelease operations for a brief interval, following the deenergization ofthe supervisory relay, so that a. false release may not occur if thecalling subscriber accidentally jiggles the switchhook to cause themomentary release of the supervisory relay. The present inventionprovides improved means controlled by the supervisory relay to initiatethe release operations, and to provide for delaying such releasemomentarily whereby the release operations are made more positive, andfalse releasing from a momentary deenergization of the supervisory relayis more surely obviated.

In the drawing, the figure shows diagrammatically release controlcircuits arranged in accordance with the present invention.

In accordance with the prior art, such as is disclosed in Fig. 3'of thepatent to V. H. Matthias No. 1,567,072 issued December 29,

1925, the release is initiated by the closure of a back contact. of thesupervisory relay,

the circuit of the release relay'being closed following the making ofthe back contact of the supervisory relay, after a delay measured by themaking of one contact of a continuously rotating interrupter and thesubsequent making of a second contact of the interrupter. The delay someasured by the interrupter has been deemed sufficient to prevent theoperation of the release relay should the supervisory relay be onlymomentarily released. The present invention, in the specific embodimentchosen for illustration here- 1927. Se ial N 1 5,231.

in, provides for the initiation of the release, at a break contact ofthe supervisory relay, the circuit of the release relay being closedafter a delay measured by the opening of one contactof a continuouslyrotating inter rupter followed by a subsequentmaking of a second contactof the interrupter. purpose of changing the initiation of the recasefrom the ,back contact ofthe supervisory relay to the front contactthereof, is to obviate failure of the initiation of release due tovibration of the selector frame which at times might prevent the backcontact from making firmly. Further, the improvement in the releasingcircuit, and pal" ticularly the provision of a newtype of interrupterprovides a delay inthe establishment'of the circuit .of the releaserelay following .the deenergization of the supervisory relay therebylessening the occurrence of premature releases. I The invention may bebest understood from a detailed consideration of the drawing whichdisclose a subscribers substation 11 connected to the trunk 12, overcontacts of relay 13 and through the winding of supervisory relay 1%.During the conversation relay 14 is held energized over the callingsubscribers line and holds relay 15 energized over an obvious circuit.When the calling subscriber desires to release the connection andreplaces the receiver on the switchhook, the circuit of relay 15 isopened at the break contact of relay 14, but relay 15 cannot releaseuntil the interrupter brush 16 leaves a grounded segment 18 of theinterrupter, since relay 15 is locked to this interrupter brush over itsown lower front contact. \Vhen brush 16 leaves a segment 18 and relay 15releases, the circuit of release relay 13 is prepared from batterythrough the winding of relay 13 over the back contact of relay 15 to theinterrupter brush 17. As soon as the interrupter advances to a pointwhere a segment 19 engages with the brush 17 this cir' cuit is completedand release takes place.

By thus placing the initiation of the release under the control of afront contact of the supervisory relay, which is not as subject tofaulty operation from external causes such as vibration as a back makecon tact would be, the release is rendered much more positive.

What is claimed is:

1, In a. signaling system, a first relay, 3.

The

second. relay,a circuit for energizingsaid first relay, means foropening said circuit, a timing device, means for holding said firstrelayaenergized under the control of said timing device for an intervalafter said circuit is opened, and a circuit for said second relayestablishednpon the release of .said first relay and after theexpiration of a second interval measured by said tiining'device;

2. In a signaling system, a first relay, a

second relay, a circuit forenergizing said first relay, a third relayfor opening said circuit, a timing device, means for holding said firstrelay energized under the control of said timing-device foran intervalafter saidcircuit'is opened 'by said=third relay, and a; circuit 'forsaid second relay established upon the release of said first-relay, andafter-the expiration of a second interval first relay, a release relay,a: supervisory relay, said supervisory relay being maintained energizedover the calling line under the control of, the calling subscriber, acircuit for energizing said first relay controlled at a front contact ofsaid supervisory relay, a timingidevice, a holding circuit for saidfirst relay under the control of said timing device eiiective for aninterval after the release of said supervisory relay, and a circuit'forsaid release relay established upon the release of said first relay andafter the expiration of a second interval measured by said timingdevice. V I

5. In a telephone system, a calling line, a first relay,a releaserelay,a supervisory relay, said supervisory relay being maintainedenergized over the calling line under the control of the callingsubscriber, a circuit for-energizing said first relay controlled at afront contact of said supervisory relay,

aninterrupter'having a plurality of con? tacts, means for-holding saidfirst relay over a first contact of said interrupter for an intervalafter the release of said supervisory relay, and a circuit for saidrelease-relay established upon the release of said first relay andafter. the closure of a second contactofsaid interrupter.

In witness whereof, I'hereunto subscribe I my name this 26th day of MayA. D., 1927.

ARTHUR RAYNSFORD.

